Duplex boiler



April 24, 1934. T. B. STILLMAN 1,955,777

DUPLEX BOILER Filed Aug. 20, 1.950

ATTORNEYS PATENT ()FFICE DUPLEX BOILER Thomas B. Stillman, South Orange, N. .11, as-

signor to The Babcock & Wilcox Company, Bayonne, N. 3., a corporation of New Jersey Application August 20, 1930, Serial No. 476,710

Claims.

This invention relates to a duplex or twin boiler that is especially suitable for ships, as it comprises two steam generating units located side by side so as to occupy a very small amount of space and so arranged that in case of failure of one of v of the parts and Fig. 5 is a side view of the furnace wall tubes and lower wall tube header.

In the drawing reference character 1 indicates the outline of the hull of a ship in which the boiler is installed. Each one of the generating units of the boiler comprises an upper steam and water drum 2 and a lower drum 3 connected by a bank of inclined tubes 4.

A furnace combustion chamber 5 is provided for each unit below and at one side of the bank 4, the

. combustion chambers being fed with fuel by fuel burners that are indicated somewhat diagrammatically by the reference character 6.

A horizontally disposed header '7 that may be slightly inclined is disposed near the bottom of each furnace 5 on the side opposite the bank of tubes 4. A bar 8 is attached to each header 7, as by weldng, for example, to retain the title 9, which protect the headers from the intense heat of the furnace. A row of vertically extending 1 tubes 10 with their lower ends connected to the header '7 is provided for each unit, the upper ends of these tubes being slightly bent and entering the corresponding upper steam and water drums 2. A row of tile 11 is installed between the two sets of tubes 10. One or more downcomer tubes 12 extend outside of the furnace from the water space of each steam and water drum 2 to the corresponding header '7. In the illustration, single downcomer tubes 12 are shown entering the lower ends of the header 7 which are preferably inclined slightly to take care of drainage and each one of the headers 7 is preferably slightly bumped on its upper side at its higher end, as indicated at 13, where some of the tubes 10 are connected, so that the danger of steam becoming pocketed in these headers is minimized.

c-shaped tile 14 may be installed around the tubes 10, as indicated in Fig. 4, on opposite sides of the row of tile 11.

The sides 16 of the boiler casing are spaced short distances from the outer rows of tubes of the banks 4 in such positions that the space between the banks and the sides 16 increase in size toward the top. Ballies 17 are provided along the upper portions of the outer row of tubes 4 of each bank to aid in directing the gases from the furnaces 5 across the tubes 4 to the outlets 18. In the operation of this boiler the radiant heat from the furnaces 5 and the hot gases heat the rows of tubes next to the furnaces more than the outer- 10st rows of tubes of the banks 4 are heated so that steam and water passes upwardly through the tubes near the furnaces and water passes downwardly through the outermost tubes between the drums 2 and 3. The bafiies 17 cause the gases to pass across the entire lengths of the tubes, instead of short circuiting through direct paths from the furnaces'S to the outlets 18. The water passing downwardly through the pipes 12 from the water spaces of the drums 2 to the headers '7 furnishes water which passes upwardly with steam that may be generated through the rows of tubes 10.

The juxtaposed sides of the two steam generating units of the boiler on opposite sides of the tile 11 are in vertical planes and the circulation systems of the two units are independent of each other, so that neither unit has to be shut down when a rupture occurs in the other one. The power generated in the remaining unit when one unit is injured is sufiicient to enable the ship to make port.

I claim:

1. In a duplex marine boiler of the express type, two independent boiler units arranged in back-toback relationship, a separate A-shaped furnace for each boiler, a steam and water separation chamber for establishing a separate water circulation for each unit, a separate lower drum for each unit, a separate bank of inclined steam generating tubes connecting each lower drum with the corresponding steam and water chamber, a lower header for each furnace located at the side of the furnace opposite the lower drum, a row of wall tubes extending upwardly from each header to the corresponding steam and water chamber, a refractory wall common to both furnaces and disposed between said rows of tubes and a separate outside downcomer leading from each steam and water chamber to the corresponding header, the tubes of said rows converging from their upper ends to a position intermediate the drums where they contact with said wall and diverging downwardly from the adjacent banks of generating tubes throughout their entire lengths.

2. In a water tube steam boiler, two separate steam and water drums adapted to be located equidistantly from a ships center line, a separate furnace below each drum, an upright wall common to both furnaces including refractory, separate headers at the base of the wall and on opposite sides of said center line, a row of wall cooling tubes each directly connecting a drum with the correspon ing header and contacting with said wall, a lower drum for each furnace located at the side opposite the header, downcomer connections between the water spaces of the drum and the headers, and a bank of inclined steam generating tubes connecting each lower drum with its corresponding upper drum and diverging from the adjacent row of wall cooling tubes throughout its length, the rows of the wall cooling tubes converging from the steam and water drums toward a position near the tops of the furnaces where a part of the refractory wall is interposed, the tubes and their connections for each furnace being capable of maintaining an independent water circulation.

3. In a duplex boiler, a furnace wall including two rows of tubes, an A-shaped furnace on each side of said wall, an upper and a lower drum on the opposite sides of said wall, a bank of inclined steam generating tubes connecting each upper drum to the lower drum on the same side of the wall, said rows of tubes being connected respectively to the circulation systems of said boilers, a refractory wall layer common to both furnaces and positioned between said rows of tubes and in contact therewi h, and horizontally disposed headers to which the lower ends of said tubes are connected, each bank of steam generating tubes diverging downwardly throughout its entire length from the adjacent row of wall tubes.

s. In a duplex marine boiler of the express type, two independent boiler units arranged in back-toback relationship, a separate A-shaped furnace for each boiler, a'steam and water drum for establishing a separate water circulation for each unit, a separate lower drum for each unit, a separate bank of inclined steam generating tubes connecting each lower drum with the corresponding steam and water chamber, a lower header for each furnace located at the side of the furnace opposite the lower drum, a row of wall tubes extending upwardly from each header to the corresponding steam and water chamber, wall material extending from tube to tube and including refractory disposed between said rows of tubes, and a separate downcomer leading from each steam and water chamber to the corresponding header, the tubes of said rows converging from their upper ends to a position intermediate the drums where they contact with said wall and diverging downwardly from the adjacent banks of generating tubes, the upper downwardly converging portions of the wall tubes being substantially straight and extending at a substantial angle to the inclination of the banks of steam generating tubes whereby the wall tubes form a stiff strut-like support for the upper drums the banks of steam generating tubes.

5. In a duplex boiler, a furnace wall including two rows of spaced wall cooling tubes, an A-shaped furnace on each side of said wall, an upper and a lower drum on each side of said wall, a bank of inclined steam generating tubes connecting each upper drum to the lower drum on the same side of the wall, said rows of tubes being connected respectively to the circulation systems of said drums, said walls also including refractory closing the spaces between the wall tubes and in contact, therewith, and horizontally disposed headers to which the lower ends of said tubes are connected, each bank of steam generating tubes diverging downwardly from the adjacent row of wall tubes.

THOMAS B. STILLMAN. 

